Birdproof spark gap for distribution lines



Patented Aug. 11, 1953 'BIRDPRD'OF SPARK "GAP FOR DISTRIBUTION LINES George H. Manke, South Milwaukee, Wis., as-

sig'nor to McGraw Electric Company, Milwau kee, Wis., a corporation of Delaware Application November 26, 1951, Serial No.258,19l l 2 Claims.

This invention relates to an improvement in spark gaps and in application provides a birdproof spark gap for electricaldistribution lines.

lightning arresters are devices that provide a weak spot in the insulation on :an electric line, thus functioning as a safety valve to let off excess voltage. The lightning arrester consists of a gap which under normal conditions insulates the line voltage from the ground. 'When a lightning disturbance occurs on the line, the surge sparks over this gap and news to the ground, thus diverting the high voltage away from transformers andyor other Valuable equipment.

Spark gap arresters to which this invention relates do not extinguish the power follow arc which fol-lows spark over from surge, but instead rely upon a fuse'or recloser to interrupt thearc.

'Double gap lightning arresters were devised to reduce the possibility of birds short circuiting the circuit. The probability that two birds would choose at the same time to light on the wires in such a position as to make a contact between two separate ga-ps, is considerably less than if one bird could -complete and thusly establish a short circuit. However, to effectively use the double gap requires quite anex-panse of porcelain insulation which, of course, adds considerably to the cost of construction. Further, double gaps are obviously not always foolproof.

Thus, the principal object of this invention is to provide a compact lightning arrester which possesses improved attributes of a double gap lightning arrest'er.

another object of my invention is to provide a single gap lightning arrester in which the active gap is enclosed in a housing made of porcelain or other insulating material.

A further object is to provide a lightning arrester which birds and/or rodents cannot short circuit.

Still another object of my invention is to place a fibre tubecircumferentiallyaround the end portion of the electrode and extending slightly beyond it to direct the spark from the electrode toward the bottom-opening in the housing.

Other objects will appear from time to time in the'course of the specification and claims.

Iillustrate my invention more or less symbolically in the accompanying drawings, in which:

Fig. l is a sectional view of my spark gap.

Fig. 2 is a sectional view of a second form of this spark gap with a fuse connection on the outside of the porcelain housing.

Like parts are indicated by like reference characters throughout.

4I illustrate two embodiments of my invention. The one shown in Fig. 1 is a simple spark gap. Iihe one shown in 2 has :a fuseattac'hment to be used to protect a transformer when such is necessary "or when uni-t construction oi a fuse and lightning arrest'e-r'is desirable.

Referring to 1, my spark gap comprises a housing I with skirts 2 extending along its outer side and a core 3 extending through the'middle portion. At the .upper end of the housing I is an insulating plug :4 and at the lower end of housing, the core is open at '5. Inserted into the insulating plug 4 is an electrodeli extendingd'ownwardly through the middle portion of Ithecore "I. At the lower end of the electrode 6 surrounding it @circ-umTerentia-lly and extending somewhat beyond the tip of the electrode "6- is a fibre tube which serves todireet the spark toward the opening .5 at the bottom of the core. A fibre lining 8 lines the core 3 in its lower portion extending upwardly in this core :a sui'ficient distance to direct the are away from the porcelain wall so as to protect it from damaging sparks or gases.

Near the'upp'er end of the housing I is a transverse opening "9 through which a conductor bolt to is inserted, passing through the electrode 3 and fastened by .nut .12 on the outer'side "of the housing. A second nut i=3 beyond the nut. 12 forms a means or making a connection the electrical distributing line when a wire connection from the line is placed between the two and the outer nut "t3 screwed rtowar'd the-nut until the wire is .held in a tightened position between thenuts. The transverse opening ll on the opposite side oitthe housing it from the line connectionhas a larger bore *portionr'hl to accommodate the bolt head ll within the circumference of the housing ii. The boltrhea-d II II :is'theneovered with :an insulating compound 51! :so that it is inaccessible to birds .or rodents.

In reverse similar manner at :the lower end of the housing I isa transverse opening 1 5 through which a :bolt I 5 is inserted and secured to the housing 1 :by means of the nut 4:8 in threaded association with the bolt Elli. On the side "of the housing opposite the line connection is a grounding connection 19 "attached 'to the bo'lt fli' 'by means of anut "20 which-clamps the grounding connection [9 in tightened position to the nut I8. A screen 2| extends over the core opening 5 at the lower end and is bent around the outer edges of the housing I. The transverse opening IS on the opposite side of the housing I from the ground connection has a larger bore portion 22 to accommodate the bolt head I! within the circumference 26 and the opening 2! at the lower end of the core is left open. Midway on the exterior of the porcelain housing 23 is a straight se'c'-' tion 28 that provides a space where a fuse clamping device 29 can be secured. Inserted in the plug 26 and extending downwardly in the core 25 in a conducting electrode '30; Surrounding the circumference, of the lower end of the electrode 30 is a fibre tube 3 i that extends slightly beyond the tip of the electrode 30. An-

other fibre tube 32 serves as a protective lining for ,the porcelain core 25 in the lower half of the housing 23.

Near the upper end of the housing 23 is a transverse opening 33 with an enlarged bore portion 34 at one end. A conductor bolt 35 is inserted through the transverse opening 33 to make contact with the electrode 30. This conductor bolt 35 is fastened to the housing 23 by a nut 36 in threaded association with the bolt 35. The conductor bolt head is recessed in the enlarged bore 34 and is covered with an insulating compound 50 to make it inaccessible to birds and rodents. The opposite end 38 of the conductor 35 provides a means for connection to the line between the nuts 31 and 39, and also a means for attaching a standard fuse support 43. The fuse support 40 holds the fuse link 4| in suspended position between the electrical terminals. The fuse support 40 and fuse link 4| is a standard attachment that can be used in combination with my spark gap when it is desired to utilize the advantages of unit construction of a fuse and lightning arrester combination.

. At the lowerend of the housing 23 is a transverse opening 42 with an enlarged bore 43, at one end through which a bolt 44 is inserted and secured by bolt head 45 and nut 46 in threaded association, the bolt head covered with an insulating compound 50 to make it inaccessible to birds and rodents. On the opposite side of the housing from the fuse 4| the two nuts 43 and 41 on the outer end of the bolt 44 serve as a means for attaching a ground connection 43.

Over the lower opening 21 of the housing 23 and extending over the housing 23 is a wire mesh 49. which prevents insects from entering the housing core.

In, the embodiment of my invention shown in Fig. 2 when .an electrical surge occurs, it will travel through the conductor 35 to the electrode 30. The spark oil" the lower end of the electrode 30 is directed downwardly by the fibre tube 3| surrounding circumferentially the lower end of the electrode 30 to the conductor 44 and from there is carried to ground by some grounding means 48. The grounding means 48 is secured by the nuts 46 and 4'! to the conductor 44 on the opposite side of the housing from the fuse link 4| so that birds or rodents cannot perch on the lower grounding conductor and reach the line terminal on the opposite side.

In the embodiment shown in Fig. 1, the spark gap without the fuse link, the surge is grounded in similar manner as in Fig. 2. The conductor in carries the surge to the electrode 6 from where the spark is directed downwardly by the fibre tube 1 until it sparks over to the conductor Ii which grounds it through the grounding connection 19. In both Figs. 1 and 2 the fibre lining 8 and 32 directs the are away from the walls of the porcelain tube and thus protects the porcelain from deterioration. In this manner, a conducting or partially conducting surface is not formed which would obviate its usefulness.

, Thereby, it can be seen that my improved bird proof lightning arrester provides a way of grounding dangerous surges on the line and is designed so that birds or squirrels cannot short circuit it.

I claim:

1. An excess-voltage protective device comprising an insulating housing having a cylindrical core extending through its length, an insulating closure at the upper end of the core, a leadin line at the upper end with an electrode attached and extending downwardly in the core, a fibre tube circumferentially surrounding the end of the electrode and extending slightly beyond it, said fibre tube embracing said electrode in tight relationship so as to preclude the passage of gases between said electrode and said fibre tube, another fibre tube lining the cylindrical core of the housing in that area where an over-voltage spark might occur, said fibre tubelining extending beyond the tip of said electrode, a screen over the opening at the lower end of the housing, and a grounding means at the lower end.

2. An excess-voltage protective device comprising an insulating housing having a cylindrical core extending through its length, an insulating closure at the upper end of the core, a

lead-in line at the upper end with an electrode attached and extending downwardly in the core,-

a fibre tube circumferentially surrounding the end of the electrode and extending slightly beyond it, said fibre tube embracing said electrode in close relationship so as to preclude the passage of gas therebetween, another fibre tube lining the cylindrical core of the housing in that area where an over-voltage spark might occur; said fibre tube extending beyond the end of said electrode, a screen over the opening at the lower end of the housing, and a grounding means at the lower end on the opposite side of the housing from the lead-in connection.

GEORGE H. MANKE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,203,349 Fox June 4, 1940 2,284,478 Roloson May 28, 1942 2,296,621 Wade Sept. 22, 1942 2,551,592 Fox May 8, 1951 

